What would you do in my place?

kind of, if she cheat on her bloke, she's simply not that into him, but it does not necessary mean she'll cheat on anyone regardless.

I'm not saying she'll 100% cheat on the next guy, that's why I said 'likely' do the same again.
Its a decent indication though. In my experience people generally have a yes or no mindset when it comes to messing about on someone.

If she is the type who would accept a proposal when she's not into the guy then she's not someone I'd want to get involved with.